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(No Model.)

R. N. R. PHELPS 82; W.'A. CLARK, Jr.

PROCESS OF TREATING THE WASTE PIGKLE LIQUOR OF IRON WORKS. No. 267,582; Patented Nov. 14, 1882.

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Uivrrnn STATES PATENT Gianna.

RICHARD N. It. PHELPS AND WILLIAM A. CLARK, JR, OF TRENTON, NEW Jl SEY, ASSIGNORS TO THE PHOENIX CHEMICAL COMPANY, OF NEW JERSEY PROCESS OF TREATING THE WASTE PlCKLE-LIQUOR F IRON-WORKS.

SPECIFICATION forming part of Letters Patent No. 267,582, dated November 14, 1882 Application filed March 28, 1882. (N0 model.)

To all whom it may concern Be it known that we, RICHARD NAFIs RHODES PHELPS, manufacturer, and WILL- 1AM ALEXANDER CLARK, Jr., M. 1)., both 5 citizens of the United States, residing at Trenton, in the county of Mercer and State ofNew Jersey, jointly have invented a new and Improved Process of Treating the Waste Pickle- Liquor ofIron-TVorks, of which process the fol- 1o lowing is a specification.

In many iron and steel working process'rs such, for instance, as the manufacture of wire, rods, bars, screws, plates, small castings, galvauized iron, &c.--the surface of the metal becomes coated with ascaleconsistingessentially of protoxideofiron. This coating is generally removed by dissolving it in a bath of dilute sulphuric acid. This acid in time becomes neutralized by the iron scale dissolved in it,

forming a solution ofa salt or sulphate of iron, technically known as pickle-liquor. This pickle-liquor, which is produced in large quantities, is generally thrown away, polluting neighboring streams and destroying fish and vegetation. Variousprocesses ofntilizingthis waste product have been suggested. One wellknown method of treatment consists in charging a vessel containing the pickle-liquor with scrap-iron, to cause it to take up an increased 0 proportion ot'iron, then running it into other Vessels and allowing it to cool, so as to deposit crystals of sulphate of iron, the mother-liquor being returned to the vessels charged with scrap-iron and a fresh portion of the pickleliquor mingled therewith to renew the process above described. The crystals thus formed are dried and exposed to heat, one method being to heat theinin the open air, so as to obtain the ferric oxide; but in this case the sulphuric 4 acid and other products of decomposition escape into the airand are lost. Another method of treatment consisted in heating the dried crystals in a closed retort and condensing the escaping vapors. This method recovered the sulphuric acid at the expense of the ferric oxide, which was very much deteriorated in quality, being of di'tierent colors in different portions of the calcining-vessel, and being hard, lumpy, and gritty, all of which qualities deteriorated its value as an article of commerce, The latter is the well-known German or Ngrdhausen process of producin gfuinin g sulphu acid, sulphate ofiron being roasted in a set of small closed crucibles with narrow nec but with mouths opening into condensers ranged in galleries. These retorts were small size, holding at most three pounds ofn terial, from which the vapors escaped as t calcination proceeded, the resulting prodi being a mixture of or cross between t'erro oxide and ferric oxide, possessing the 'uni sirable qualities above referred to, while t escaping vapors were condensed to form t well-known Nordhausen fuming acid. So i as our knowledge extends, all other process of recovering ferric oxide heretofore suggest or employed have been based upon cheinic reaction or embodied it in some portion or some period of the process, thus involving'tl .use of substances so expensive as to neutrali or destroy the commercial value of the produ obtained.

The object ot'ourinvention is simultaneous to recover by one single operation the ferr oxide, sulphuric acid, and other products 00. tained in waste pickle-liquor by its physio: decomposition without the use of chemic: agents or the admixture of foreign substance This end we attain by evaporating the pickli liquor, drying the resultingcrystals of sulphat of iron in the usual \vell-ki1own ways, an grinding them to line powder, then exposin thissulphate to a high degree ot'heat of abou an incipient redness, though we sometime employ as high as a cherryred heat-sa 1,300 Fahrenheit-in a retort, vessel, 0 chamber, through which aregulated current'c air passes. The heat decomposes the sulphat into sulphuric'acid vapor, sulphurous tiOlt gas, and the sesquioxide of iron. The firs and second of these products pass into suitabli receivers, tanks, or condensing-chambers, ant the third is left on the floor of the heating chamber or retort.

The accompanying drawings represent om convenient form of apparatus for carrying on the objects of our invention. The details 0 such apparatus, however, maybe moditied ii various well-known ways without departing. from the spirit of our inv eution, and the apparatus, being well-known, is not hereili claimed.

e 1 represents a front elevation of the us, partly in vertical section on the at Fig. 2; and Fig. 2, a plan or top view ame, partly in section, on the line 2 2 'nace, A, is shown as provided with the red-doors and draft-regulating devices. 5 of retorts or heating-chambers, B, exrough this furnace at each end, being d in front with charging-doors I) and :gnlating valves 1) and in rear with espes B, which terminate in a condenser, ny suitable well-known construction, 11 represented in the drawings being ll-known form of surface'condenser. A leads from this condenser to a fan, E, r suitable draft-producing apparatus. trrying out the objects of our invention ce the dried pulverized sulphate ofiron ad from the waste pickle-liquor in the and heat it to ateniperature of not less ,000 Fahrenheit. The retort of course is its contents from contact with the pro bf combustion in the furnace. Air, being ed to the retort in regulated quantities, to convert the protoxide of iron into a oxide, while the sulphuric-acid vapors llphurous-acid gas evolved are carried draft out of the retortinto the condenser, ion of the products thus carried over bendensed intoliquid sulphuric acid, which is in the reservoir C at thebottom theremay be conducted by pipes to any suitreceptaele. The escaping sulphurousacid gas drawn ofl? through the fan may be conducted to other receptacles or condensingchambers and treated in well-known ways to recover the sulphurous acid. The residuum remaining in the retort, as above remarked, is a sesquioxide of iron, constituting a rouge or pigment ot' a rich red color, valuablefor many purposes in the arts. The color of this ferric oxide or rouge varies according to the temperature of the retort and the length of time the process lasts, as is well known. \Ve have given the best conditions attained in practice, but do not limit ourselves to the precise temperatures stated.

WVe claim as our invention- The hereinbetore-described process of treating pickle-liq nor from the cleanin g-tubs of ironworks, which process consists in evaporating the pickle-liquor, drying and pulverizing the resulting crystals of sulphate of iron, beating them to a temperature varying between an incipient and a cherry red in a retort or other chamber, into which air is admitted in regulated quantities, and condensing the escaping vapors, whereby ferric oxide and sulphuric and sulphurous acid gases are simultaneously recovered by a singue continuous operation.

In testimony whereof we have hereunto subscribedour names this th day ofMareh, 1882.

RICHARD NAFIS RHODES PHELPS. WILLIAM ALEXANDER CLARK, JR. \Vitnesses:

B. M. PuILLiPs, G. H. HALL. 

